/* global hexo */

'use strict';

const moment = require('moment');
const { isMoment } = moment;

hexo.extend.helper.register('compare_date', function(date1, date2) {
  if (!date1) {
    return -1;
  }
  if (!date2) {
    return 1;
  }
  const m1 = isMoment(date1) ? date1 : moment(date1);
  const m2 = isMoment(date2) ? date2 : moment(date2);
  const diff = m1.diff(m2);
  if (diff < 0) {
    return -1;
  } else if (diff > 0) {
    return 1;
  } else {
    return 0;
  }
});